Lazy H (oz12083)

About this Plan

Lazy H. Radio control sport biplane for electric power, using a geared Astro 25 cobalt motor. Wingspan 49-1/2 in, wing area 810 sq in.

Quote: "The Lazy H Bipe for electric RC, by Scott Hartman. A lot of enjoyable, laid-back flying is in store for those who build this three-channel bipe, designed to go together quickly and perform well on a geared Astro 25 power system.

Well, the creative part of me has been working again. This time the result is a geared 25-size electric biplane, a model I call the 'Lazy-H.' As the name implies, this airplane builds easily and fast. It lacks the difficult features found on most bipes such as wire cabin struts, wheel pants and wing struts. It's designed for the true Sun-day flier who lacks the time to build a more complex model.

The Lazy-H has excellent low speed characteristics and is capable of short takeoffs and landings. The model can easily take off in 15 to 20 feet, and landings are a joy with the extra drag associated with a bipe. The prototype is flown with rudder, elevator and mo-tor control. It's capable of loops, rolls, horizontal eights, spins and most other simple maneuvers.

An Astro Flight geared 25 with 14 Sanyo SCR cells does an excellent job of powering the model. This was my first geared electric system, and to say I was impressed would be an understatement. The motor turns a 13 x 8 Rev-Up propeller slowly and lifts the 5-pound model off the ground in short order. Endurance is achieved by cutting back on the throttle when full power isn't needed. I normally achieve 5 to 7 minutes by flying a mixture of full throttle takeoffs, mid-speed aerobatics, low speed flight and touch-and-go's. This airplane is well suited to schoolyard type flying in a limited area.

CONSTRUCTION Proceed by first cutting out the sheet balsa pieces to make a kit. Use light grade balsa unless noted. Lone Star Models (1623 57th St., Lubbock, TX 79412; 806-745-6394) will ship the desired grade if specified on the order. All glue joints should be made with medium or thick CA glue and accelerator.

TAIL SURFACES: Build the tail surfaces over the plans using 3/16-inch thick hard balsa stick and light sheet stock. I used light balsa sheet for the rudder and tapered sheet for the elevator. Join the two elevator halves with a short piece of dowel.

FUSELAGE Begin by building the cabin struts out of 3/16 x 3/4 spruce. Pin the 3/32 balsa fuselage side to the plan and glue the cabin strut and doublers in place. Mark the locations of the formers on the side. Make the other side the same way.

Tack-glue formers F2A, F3, F4B, F5 and F6 on one of the fuselage sides. The angle that the formers join the side should be estimated based on the plans. Tack-glue the fuselage sides together at the rear, then tack-glue the formers to the remaining side and adjust until the fuselage is straight. When satisfied, glue the formers solidly to the sides. Install the flexible pushrods (I used Sullivan Golden-Rods on the prototype).

Glue on the 1/8-inch lite-ply landing gear block and the 3/8-inch triangle stock. Sheet the bottom rear with light 1/16 balsa. Sheet the bottom of the fuselage from the lite-ply landing gear block to F2A with 1/8-inch light balsa. Glue Fl to the sides with the side thrust and down thrust as per the plans. Install the 1/2-inch balsa triangle stock and scrap pieces to the nose as shown.

Test fit the motor into the nose. You will have to replace the gearbox screws with ones 1/8-inch longer to compensate for the thickness of firewall F1. Glue F2 B to F2A while test fitting the motor..."

Direct submission to Outerzone.

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